Elevator safety apparatus



Jam-31, 1939. F. HYMANS ELEVATOR SAFET Y APPARATUS Filed July 19, 1957 INVENTOR ATTORNEY Patented Jan. 31, 1939 UNITED STATES rarer ELEVATOR SAFETY APPARATUS Application July 19, 1937, Serial No. 154,359

6 Claims.

The invention relates to safety apparatus for elevators.

It is the practice in elevator installations to provide the elevator cars with safety brakes.

of the body through this roping to effect the ap-' plication of the brake. The invention is particularly directed to speed controlled mechanism for effecting the application of elevator safety brakes.

It is the object of the invention to provide speed controlled mechanism for effecting the application of elevator safety brakes which is of simple construction, reliable and positive in operation and which operates in a minimum of time.

The invention involves utilizing a force which is a function of the driving torque of speed responsive mechanism driven by the movable body of an elevator system directly to operate the mechanism for effecting the application of the safety brake for the body.

The invention will be described as applied to an arrangement in which the safety brake is provided for theelevator car although it is also applicable to arrangements in which the counterweight is provided with a safety brake. In the arrangement which will be described, the speed responsive mechanism is in the form of a fly ball governor which is driven by a rope connected to the car through an actuating connection for the safety brake. Clutch jaws are provided for gripping the governor rope. The jaws are biased to rope gripping position but are normally held by a latch in non-gripping position. In carrying out the invention as applied to such arrangement, a trip rotated by the governor driving mechanism is moved into position by the governor, when the car overspeeds a certain amount, where it strikes the latch in its rotary movement. The force with which the trip strikes the latch, being a function of the torque driving the governor, effects a positive and immediate release of the latch, permitting the jaws to clutch the governor rope and apply the brake.

The features and advantages of the invention will become apparent from the specification and appended claims.

In the drawing:

Figure 1 is a schematic representation of an elevator installation embodying speed controlled mechanism for effecting application of the elevator safety brake in accordance with the invention;

Figure 2 is an enlarged view, with parts omitted, of the speed controlled mechanism shown in Figure 1; and

Figure 3 is a detail taken along the line 3--3 of Figure 2.

Referring to Figure 1, hoisting ropes H] for the car H and counterweight (not shown) pass over the hoisting drum l2 at the top of the elevator shaft, This drum is driven by means of a hoisting motor I3 to effect the raising and lowering of the car and counterweight. An electromechanical brake i4 is employed to aid in bringing the motor to a stop and to hold the car while at rest. Guide rails l5 are provided for the elevator car. The bottom guide shoes for the car are designated it, while the top guide shoes are designated ll. These guide shoes cooperate with the guide rails to guide the car in its movement up and down the elevator shaft.

The governor rope 2i extends around the governor sheave 22 at the top and a tensioning sheave 23 at the bottom of the elevator shaft, the tensioning sheave being provided with tensioning weights 24. Governor sheave 22 is mounted on a governor shaft 25 which is geared to spindle 26. The governor is illustrated as of the fly ball type, being provided with centrifugal weights 27, weight arms 28, sleeve 3%, connecting links 3! and resisting spring 32, The governor rope is connected to one arm 33 of a bell crank lever 34 pivotally mounted on the upper cross channels 35 of the car frame. The other arm of thislever is connected by a rod 36 to a similar bell crank lever 31 pivotally mounted on the cross channels at the other side of the car. A spring 38, arranged on rod 36 between a stop 39 on the rod and a fixed guide M for the rod, biases the levers to the positions illustrated. These levers are adapted,-

upon upward movement of arm 53 by the governor rope to swing lever 34 counterclockwise, to operate lift rods 4! to effect the application of the rail clamps 42 of the safety brake to theguide rails.

Referring also to Figure 2, to swing arm 33 of bell crank lever 34 upwardly to effect the application of the safety brake, the governor rope is gripped by eccentric clutch jaws 43 and 44. These jaws are rotatably mounted on shafts 45 and 46 supported by lugs arranged on, the governor base 49. These jaws are caused to move together by spur gear segments 41 and 48. As shown in Figure 1, shaft 45 is mounted on a movable rod 58, the outer end of the rod being slidably supported in an aperture of an additional lug 5| provided on the governor base. A spring 52 abutting against this lug and a shoulder 54 on the rod biases jaw 43 toward jaw 44, this spring determining the pressure with which rope 2| is gripped by the jaws as it passes between them when they are released. Thus governor rope 2| is allowed to slide through jaws 43 and 44 but at the same time exerts a pull sufficient to apply the safety brake.

The jaws are normally latched in the position illustrated, disengaging the governor rope. The latch mechanism comprises a vertically extending rod 55 connected at its lower end to jaw 44 and extending upwardly through an aperture 56 in lug 51 formed on the governor stand 58. At the top this rod is bent over to form a latch member 60. An arm 59 of a trigger 6| extends beneath this latch member, thereby supporting the rod 55 in position to hold the jaws disengaged from the rope. The trigger Si is pivotally mounted on a pin 62 supported by an additional lug 63 provided on the governor stand. The jaws are biased to rope engaging position by the weight 64 secured to the rod, this weight also acting to hold the rod 55 in latched position with the latch 60 resting on trigger 6|.

The other arm 68 of the trigger 6| is adapted to be engaged by a trip 65 to release the latch member 69 when overspeed conditions occur. This trip is carried by the governor sleeve 30 and may be in the form of a plurality of lugs 65 arranged radially around the sleeve to form a multi-lobed cam. The governor spindle is preferably provided with a key 51 for imparting a positive drive to the sleeve at this point. The lugs 66 are preferably shaped, for example as shown in Figure 3, to obviate too sharp a blow when the arm 68 of the trigger is hit by the trip to release the latch.

In operation, the elevator car is caused to move up and down the hatchway by motor !3, the car transmitting motion to the governor through governor rope 2i. So long as the elevator runs at or below normal full speed, no relative motion takes place between the car and the governor rope. However, in the event that the car in its downward motion attains a speed which is a certain percent greater than normal full speed, depending upon the particular installation, the governor sleeve 30 is raised by the centrifugal force of the fly balls sufficiently for the trip 65 to strike the trigger 6! in its rotary movement, knocking trigger arm 59 from beneath latch member 5! This allows clutch jaws 43 and 44 to fall, aided by weight 64, into position to grip the governor rope. This gripping action retards movement of the rope, thereby acting to overcome the force of spring 38 to move bell crank levers 34 and 31 into position to lift rods 4i, thereby effecting the application of the rail clamps to the guide rail. This causes the elevator car to be retarded and finally brought to a stop. When the rail clamps have been released from the guide rails, the jaws 43 and 44 may be manually reset and the trigger 6! moved beneath latch 60, placing this mechanism in condition for another operation.

It will be seen that latching and latch releasing mechanism for the clutch jaws, such as above described, embodying the invention, is of simple construction and reliable in operation. It is to be understood that such mechanism may be utilized in conjunction with various types of safety brakes and speed responsive governors and that the arrangement of the mechanism for gripping the governor rope may be varied. Also, the arrangement of the latching and latch releasing mechanism may be varied so long as a positive force which is a function of the driving torque of speed responsive mechanism driven by the movable body is utilized directly to effect the release of the latch. It is therefore intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In an elevator system in which a body movable in the elevator hatchway carries a safety brake for application to the guide rails for the body to stop the body during its descent, in which speed responsive mechanism is driven by said body by means of a rope operatively connected to said safety brake, and in which means is provided for gripping said rope to cause the application of said safety brake to said rails; means for latching said gripping means in position disengaging said rope; and means rotated by said rope during movement of said body and movable by said speed responsive mechanism, upon said body attaining a certain speed, into position to directly engage said latching means and exert thereon a force in a plane at right angles to the axis of rotation of said rotated means to unlatch said latching means, thereby releasing said gripping means for gripping said rope.

2. In an elevator system in which a body movable in the elevator hatchway carries a safety brake for application to the guide rails for the body to stop the body during its descent, in which a governor is driven by said body by means of a rope operatively connected to said safety brake, and in which a clutch is provided for gripping said rope to cause the application of said safety brake to said rails; means for latching said clutch in position disengaging said rope, said latching means having a catch member; and means rotated by said rope in driving said governor and movable by said governor, upon said body attaining a certain speed, into position to directly engage said catch member and move it in a plane at right angles to the axis of rotation of said rotated means, releasing said latching means to permit said clutch to grip said rope.

3. In an elevator system in which a body movable in the elevator hatchway carries a safety brake for application to the guide rails for the body to stop the body during its descent, in which a fly ball governor is driven by said body by means of a governor rope connected to actuating mechanism carried by said body for said safety brake, and in which a pair of jaws are provided for gripping said rope to cause operation of said actuating mechanism to effect the application of said safety brake to said rails; means for latching said jaws in position disengaging said rope; and camming means carried by the sleeve of said governor, said latching means having a member positioned to be engaged by said camming means in the rotary movement thereof upon said sleeve being lifted to a certain point due to said body reaching a certain speed, said camming means upon engaging said member exerting a force thereon in a plane at right angles to the axis of rotation of said camming means, moving it into position to release said latching means, thereby causing said latching means to be released by a positive force derived from the governor driving torque.

4. In an elevator system in which a body movable in the elevator hatchway carries a safety i brake for application to the guide rails for the body to stop the body during its descent, in which a fly ball governor is driven by said body by means of a governor rope connected to actuating mechanism carried by said body for said safety b'rake, and in which a pair of jaws are provided for gripping said rope to cause operation of said actuating mechanism to effect the application of said safety brake to said rails; a member connected to one of said jaws; a second member engaging said first named member to latch said jaws in position disengaging said rope; and camming means carried by the sleeve of said governor, said second member being positioned to be struck by said camming means in the rotary movement thereof upon said sleeve being lifted to a certain point, thereby causing said second member when struck by said camming means to be moved, by a force derived directly from the torque exerted in rotating said governor, into position to release said jaws for gripping said rope.

5. In an elevator system in which a body movable in the elevator hatchway carries a safety brake for application to the guide rails for the body to stop the body during its descent, in which a fly ball governor is driven by said body by means of a governor rope connected to actuating mechanism carried by said body for said safety brake, and in which a pair of clutch jaws are provided for gripping said rope to cause operation of said actuating mechanism to efiect the application of said safety brake to said rails; a latching member connected to one of said jaws;

a pivoted trigger having an arm engaging said latching member to latch said jaws in position disengaging said rope; and a cam carried by the sleeve of said governor, said trigger being positioned to be struck by said cam in the rotary movement thereof upon the cam being lifted to a certain point due to said body reaching a certain speed, the cam in striking said trigger knocking the trigger out of position engaging said latching member to release said latching member and thus permit said jaws to engage said rope.

6. In an elevator system in which a body movable in the elevator hatchway carries a safety brake for application to the guide rails for the body to stop the body during its descent, in which a fly ball governor is driven by said body by means of a governor rope connected to actuating mechanism carried by said body for said safety brake, and in which a pair of clutch jaws are provided for gripping said rope to cause operation of said actuating mechanism to effect the application of said safety brake to said rails; a weighted rod connected to one of said jaws and extending vertically upward therefrom, said rod having a latch member formed on its upper end; a pivoted trigger having an arm extending beneath said latch member to hold said jaws in position disengaging said rope; and a multi-lobed cam carried by the sleeve of said governor so as to be rotated upon rotation of said governor by movement of said body and to be lifted by the extensions of said fly balls of the governor as the speed of said body increases, said trigger having another arm positioned to be struck by said cam in its rotary movement upon the lifting of said cam to a certain point due to said body reaching a certain speed, the cam in striking said arm of said trigger knocking the trigger from beneath said latch member to release said latch member and thus permit said jaws to drop into position engaging said rope.

FREDERICK HYMANS. 

